The invention relates to a bolt for clamping adjoining parts, which have openings, including a bolt body which can be introduced into the openings from one side of the adjoining parts, an actuator which can be actuated from one end of the bolt body, as well as clamping means, which are mounted in the bolt body and are partially movable from out of the bolt body with the actuator.
A bolt of the type mentioned above is known from EP 2 333 356 B1, with which two or more adjoining parts of any kind, which have openings, can be clamped to each other. Bolts of this type include a bolt body into which a threaded spindle can be screwed in from the one end face, which threaded spindle extends beyond the bolt body at this end and at the same time serves as a hand wheel, usually with greater diameter in relation to the bolt body. Provided at this end of the bolt body is a sliding sleeve, which is arranged non-rotatable but displaceable in the longitudinal direction and protrudes radially outwardly beyond the bolt body. At the opposite end, the bolt body has radially outwardly extending through openings, through which clamping element in the form of balls can be moved outwards far enough as to project beyond the outer circumference of the bolt body at this point. The radial outward movement of these balls is achieved with the aid of the threaded spindle, which, in the area of the clamping elements, has a conical, frustoconical surface which tapers towards the end away from the handle. As soon as this frustoconical surface comes into contact with the balls and the threaded spindle is screwed further forward, this conical surface presses the balls outwards so that they project beyond the outer circumference of the bolt body. Prior to clamping, the balls are in the retracted state within the bolt body. As a result, it is possible to slide the bolt with the end having the balls through the aligned openings of the adjoining parts until the balls are in front of the outer surface of the parts. Now, the thread spindle is screwed forward with the aid of the handle, so that the balls are initially moved outwards. The handle of the threaded spindle, which has a greater diameter than the external diameter of the bolt body, is still at a distance from the sliding sleeve. By further forward screwing of the threaded spindle, the stop surface of the handle at the end face progressively approaches the sliding sleeve and ultimately presses the latter against the outwardly moved balls at the other end of the bolt. Thus, with only a few manipulations, a simple, very high load-bearing and play-free connection of two or more adjoining parts is thus possible.
DE 199 17 209 C2 discloses another bolt of the afore-mentioned type. In this bolt, a support element of greater diameter is arranged on the bolt body and is either fixedly connected to the bolt body or can be changed in position on the bolt body by engaging with an internal thread into an external thread provided on the outside of the bolt body. Clamping of the adjoining parts is again realized by means of balls as clamping means between the balls and the support element.
DE 202 19 317 U1 discloses a further bolt of the afore-mentioned type. This bolt also has a support element of greater diameter than the bolt body. The actuator, for example a threaded spindle, has a handle which is configured pot-like and overlaps the support element. Clamping of the adjoining parts is again realized by means of balls as clamping means between the balls and the handle.
For example, such bolts are used for clamping adjoining parts in conjunction with welding tables, with which objects can be clamped and welded or otherwise processed. In addition, there are also numerous other possible applications for welding tables, for example, for the measuring of devices or the like. Such welding tables are known, for example, from EP 0 541 904 A1 or IDE 91 09 540 U1.
Welding tables have in their surface and, optionally, also in the side panels of the table top, a plurality of mostly round openings which are arranged in a uniform grid dimension. In addition, the welding tables have a wide range of accessories with which the clamping of objects is possible. Thus, essentially angular supports are provided, which also have round openings or also oblong openings. These supports can be connected to one another or to the table by clamping elements, such as clamping bolts, which can include a threaded screw with associated nut. In addition, the afore-mentioned bolts also find application, which are inserted from one side into the openings of the table and are supported within the opening or on the underside of the table top.
In addition, screw clamps are used in connection with welding tables as clamping element and also serve to clamp objects. Various stops with round and/or oblong openings and prisms are also known as further accessories.
The openings in the welding tables and in their accessories are usually designed as round throughbores, which can be chamfered, i.e. can have a frustoconical depression.
When balls are used as clamping means in the bolts, there is, however, the disadvantage that the balls only engage in a point-shaped or linear manner in the region of the opening on the one of the parts to be clamped so that clamping forces can cause material deformations.
Such material deformations can be avoided, when there is a form-fitting connection between the clamping means of the bolts and the adjoining parts to attain a distribution of the clamping forces. When using the afore-mentioned threaded screws with associated nut as a clamping element, both the head of the threaded screw and the nut rest formfittingly on the parts to be clamped. In the case of chamfered throughbores, connecting bolts are known with a countersunk head arranged on the bolt body and a countersunk head screw which makes possible a solid screw connection of two or more adjoining parts. However, both the threaded screw with associated nut and the connecting bolt can not be handled from one side.
DE 10 2011 101 096 A1 describes a bolt of the afore-mentioned type, in which the clamping means is designed as at least one sliding element mounted in the bolt body in fixed rotative engagement, and the outer portion of the sliding element has a supporting surface in the form of an outer surface segment of a truncated cone or an annular supporting surface. Though this results in a form-fitting connection between the sliding elements and the parts to be clamped. However, due to frictional forces, problems may arise when loosening the connection, i.e. it is not guaranteed that the sliding elements will move again into the interior of the bolt body in order to be able to pull the bolt out of the openings.
Reference is made to the content of the publications cited in the art and made as subject of the present application.